#include"my_stdio.h"
#include<stdlib.h>
#include<sys/stat.h>
#include<sys/types.h>
#include<fcntl.h>
#include<string.h>
#include<unistd.h>
mFILE* mfopen(const char *filename,const char *mode)
{
  int fd = -1;
  if(strcmp(mode,"r") == 0)
  {
    fd = open(filename,O_RDONLY);
  }
  else if(strcmp(mode, "w") == 0)
  {
    fd = open(filename,O_CREAT|O_WRONLY|O_TRUNC,0666);
  }
  else if(strcmp(mode, "a") == 0)
  {
    fd = open(filename,O_CREAT|O_WRONLY|O_APPEND,0666);
  }
  if(fd < 0) return NULL;
  mFILE *mf = (mFILE*)malloc(sizeof(mFILE));
  if(!mf) 
  {
    close(fd);
    return NULL;
  }
  mf->fileno = fd; 
  mf->flag = FLUSH_LINE;
  mf->size = 0;
  mf->cap = SIZE;
  return mf;
}
void mfflush(mFILE *stream)
{
  if(stream->size > 0)
  {
    write(stream->fileno,stream->outbuffer,stream->size);
    fsync(stream->fileno);
    stream->size = 0;
  }
}
int mfwrite(const void *ptr,int num,mFILE *stream)
{
  //拷贝
  memcpy(stream->outbuffer+stream->size,ptr,num);
  stream->size += num;
  //检测是否刷新
  if(stream->flag == FLUSH_LINE && stream->size > 0 && stream->outbuffer[stream->size-1] == '\0')
  {
    mfflush(stream);
  }
  return num;
}
void mfclose(mFILE *stream)
{
  if(stream->size > 0)
  {
    mfflush(stream);
  }
  close(stream->fileno);
}
